I really like it when pages use really subtle animation to enhance different page elements. Check out the E-Junkie site and their little flame dude in the stamp as their logo. Every once in a while he blinks and it's a pretty cool effect. They use an animated GIF to achieve this effect, so I thought I'd give you an example of my own.
Chris Spooner at Spoon Graphics has designed a very cool "Frankenspoon" monster. I modified ol' Frankenspoon a bit (and made him blink) and used him in the header of an example site. Also, the highlight on the top border of the site moves back and forth once in a while.